Starfall

Starfall is an arcane spell available to druids, Priestess of the Moon, and possibly mages, priests, sorcerers, warlocks and wizards. The caster turns starlight into devastating missiles. The caster calls down starlight that solidifies into a destructive missile of matter and energy. The missiles appear as searing stars from the air above the targets, rocketing down into them with devastating explosive power. A caster is able to concentrate, and target two creatures,
structures or objects with one starlight missile each that causes force damage. It can target different creatures, or the same creature repeatedly. However it cannot target the same creature with both missiles at the same time.WRPG 168WoWRPG 340

At the peak of her experience, a priestess of the moon may call down a furious shower of falling stars that cause massive destruction amongst enemy forces. This catastrophic power, given to the priestess by Elune herself, achieves its full duration as long as the priestess stays in the spell’s vicinity.W3Man 56

The most powerful spell in the arsenal of the Priestess of the Moon. The spell is a much more powerful version of Starshards, an ability all Night ElfPriests may learn. While a priestess of Elune channels this ability, she is lit up by light, and stars come crashing down from the skies, striking her enemies with the force of Elune. This ability was especially used by Tyrande Whisperwind during the many battles of the third war. She aided her allies in defeating many demons with it during the battle of Mount Hyjal, and when she was to protect the bridge over the river Arevass in Loradaeron. She, with this spell alone, held back an army of undead. She was swept downriver when the bridge collapsed and stranded in a watery valley in the middle of the plaguelands when the Scourge crept in on her. Through extensive use of starfall, she held their assaults off until Illidan came to her rescue.

Omen from the Lunar Festival has this ability too.

As proven by the spell, Tyrande Whisperwind can do an average of two and a half thousand damage every 2 seconds, twelve thousand for its full duration.